Most prior art electronic devices that can compute momentum often use a push-type movement sensor to make the sensor generate a response whenever the user conducts a movement (for instance, walking or running a step, or jumping one time in the rope jumping exercise), and then an electronic calculator computes and records the number of times of the related responses of the sensor.
However, such device must use a push-type sensing switch to sense the changes of the user's movements. In installation, the position to install such a push-type sensing switch is restricted, and the switch will be easily damaged by abrasion and thus fail. Most importantly, the accuracy of the sensing is often incorrect. As this kind of push-type switch must use the push of the user's body weight to make the two contact conductors in said switch mutually contact for generating a responsive signal, if and when the installation position is slightly deviated, or the user's movement is incorrect, wrong responsive signals may be generated. This, in turn, generates incorrect computed results.